In the related art, an image forming apparatus which is provided with a rechargeable battery and able to operate even when power supply thereto is stopped due to a power failure of the commercial, i.e., local public, power supply, is known.
However, where the image forming apparatus is configured to maintain all of its functionality in a usable state when a power failure or interruption occurs, the usable time of the image forming apparatus once a power failure has occurred is short because the battery can rapidly discharge all of its power to maintain all of the image forming apparatus' functions.